Typically, the minimum rotational speed of a spindle motor is determined based on a fluid dynamic bearing to be able to maintain a required flying amount at 65 degrees Celsius. This temperature is the upper limit for the guaranteed operating temperature of the HDD. Accordingly, the rotational speed of the HDD is based on 65 C regardless of the ambient temperature of the HDD. As a result, there may be restrictions to the reduction of power consumption of the HDD in regards to the rotational speed of the spindle motor.
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